Steam Hair-Styling Appliance

ABSTRACT

The invention relates to a steam hair-styling appliance (1) for shaping the hair, comprising: —a first jaw (2) and a second jaw (3), arranged opposite one another and hinged together, a first treatment surface (4) being supported by the first jaw (2) and a second treatment surface being supported by the second jaw (3), the first and second treatment surfaces being configured to grip at least one lock of hair, and —a liquid reservoir, said first and/or second jaw (2, 3) additionally comprising: —a system for vapourising (7) the liquid to form steam, comprising at least one vaporisation chamber (71) which has an inner surface and is in communication via an injection tube (74) with the liquid reservoir, said injection tube (74) having a free end which forms a point for injecting the liquid into the vaporisation chamber (71), and —a system for dispensing (7) the steam from the vaporisation system (7), comprising at least one steam dispensing port (75) directed toward the at least one lock of hair, characterised in that the injection tube (74) comprises an opening extending substantially along the length of said injection tube (74) from the free end which forms the injection point, said opening being a shape that allows the liquid coming from the reservoir to run into the vaporisation chamber (71) in the event of accumulation and deposition of scale at the free end of the injection tube (74).

FIELD OF THE INVENTION

This invention relates to the field of hair-styling appliances, and more specifically to steam-generating hair-styling appliances.

PRIOR ART

Hair-styling appliances generally consist of two jaws which are hinged together and opposite each other, each having a treatment surface, at least one of which is heated, the other one enabling a lock of hair to be brought into contact with the heated surface. The hinged jaws generally comprise an area for holding the appliance at the end comprising the hinge in order to be able to manipulate the appliance and in particular to be able to make the jaws pivot to a closed position so as to grip a lock of hair.

In a general operation mode, hair is shaped, for example straightened, by gripping a lock of hair at the roots and then sliding the hair-styling appliance along the length of the lock, from the roots of the hair to the ends.

Variously-shaped treatment surfaces can be arranged on the jaws according to the desired hairstyle. Typically, treatment surfaces of matching shapes are used, substantially flat for straightening, curved for curling, or corrugated for crimping.

It is also possible to direct steam onto the hair to improve the shaping of the hair. For example, WO2014064660 describes a hair-styling appliance comprising a liquid reservoir and in which a jaw comprises a vaporization system and a system for dispensing steam to a lock of hair. A liquid, typically water or a hair care product, is stored in the reservoir and injected via a duct into the vaporization system comprising a chamber. Under the action of a heating means, when the liquid comes into contact with the vaporization chamber it changes to steam and is able to reach the dispensing system, which comprises a plurality of slit-shaped ports oriented so as to direct the steam onto a lock of hair gripped between the two treatment surfaces. However, a rapid increase in the temperature of the liquid, which may contain minerals, in the vaporization chamber may lead to a gradual deposition of scale or limescale on the inside or at one end of the duct and to an eventual clogging thereof. This phenomenon consequently causes the hair-styling appliance to malfunction and reduces the useful life of the hair-styling appliance.

Furthermore, to improve the ergonomic and esthetic properties of hair-styling appliances, the hair-styling appliance should be made more compact, in particular by reducing the volume of the vaporization system. However, reducing the volume of the vaporization chamber consequently reduces the useful life of the hair-styling appliance because scaling will occur faster, typically at the end of the duct where the liquid is injected into the vaporization chamber.

It is recommended to use distilled water to reduce the risk of scaling in the appliances. Unfortunately, such a solution is inconvenient for users and rarely applied in practice, meaning that the appliances remain at risk of scaling and that a technical solution rather than a use solution should be found.

To this end, adding a means for collecting and eliminating the scale that accumulates in the vaporization chamber in the hair-styling appliance has been proposed. An example of such a device is described in FR2987242, which proposes a collection vessel comprising rock wool for absorbing the scale and a scraper blade at the end of the vessel for scraping the surface of the vaporization chamber. However, such a device is complex and adversely affects the compactness of the hair-styling appliance.

Hence there is still a need for a solution which makes it possible to increase the useful life of a hair-styling appliance with regard to scaling but without complicating the design thereof.

SUMMARY OF THE INVENTION

One of the purposes of the invention is to propose a solution to the problems identified, and in particular to improve the useful life of a hair-styling appliance, especially with regard to scaling, without reducing its compactness and in particular while keeping the height of the vaporization chamber to a minimum.

According to a first embodiment, a steam hair-styling appliance for shaping hair is proposed, comprising:

a first jaw and a second jaw arranged opposite one another and hinged together, a first treatment surface being supported by the first jaw and a second treatment surface being supported by the second jaw, the first and second treatment surfaces being configured to grip at least one lock of hair,

a liquid reservoir,

said first and/or second jaw additionally comprising

a system for vaporizing the liquid to form steam, comprising at least one vaporization chamber which is in communication via an injection tube with the liquid reservoir, said injection tube having a free end which forms a point for injecting the liquid into the vaporization chamber,

a system for dispensing the steam from the vaporization system, comprising at least one steam dispensing port directed toward the at least one lock of hair,

characterized in that the vaporization chamber comprises an inner surface covered at least partially by a hydrophobic layer positioned below the injection point.

The hair-styling appliance proposed according to this first embodiment may comprise the following characteristics, taken alone or in combination:

the hydrophobic layer comprises polytetrafluoroethylene (PTFE); the hydrophobic layer is solely positioned below the injection point and over a surface comprised between 10 mm² and 2,000 mm², preferably comprised between 100 mm² and 1,000 mm², and more preferably comprised between 500 mm² and 600 mm², for example 552 mm²; the hydrophobic layer has a flat shape, preferably substantially rectangular or triangular or alternatively, the hydrophobic layer has a three-dimensional shape comprising inclined planes, for example a pyramid shape or a truncated pyramid shape; the hydrophobic layer is an element mounted in the vaporization chamber and held in place by an immobilization device comprising an element for centering said mounted element relative to the injection point; the centering element preferably comprises a centering half-pin formed in the vaporization chamber and designed to cooperate with a matching notch formed in the mounted element; or alternatively, the vaporization chamber is obtained by casting a metal material and in which the hydrophobic layer is formed by applying a hydrophobic material to the inner surface of the vaporization chamber, for example like a paint or coating; the inner surface of the vaporization chamber also comprises a hydrophilic layer; the hydrophilic layer is at least partially covered by the hydrophobic layer; the hydrophilic layer comprises a woven material, and preferentially a glass fabric; the injection tube is beveled at the free end forming the injection point; the injection tube has a portion which is cut in half; the vaporization system also comprises a secondary vaporization chamber communicating fluid to the vaporization chamber, said secondary vaporization chamber comprising a plurality of baffles; the steam dispensing system comprises a dispensing chamber in which the at least one steam dispensing port is arranged, said dispensing chamber receiving steam from the vaporization chamber. The dispensing chamber is preferably arranged laterally to the vaporization and secondary vaporization chambers; the vaporization system comprises a heating means located at least partially underneath the vaporization chamber and comprising a so-called positive temperature coefficient (PTC) electrical resistor or a ceramic; the first and the second treatment surfaces are substantially matching and flat or curved or corrugated.

According to a second embodiment, a steam hair-styling appliance for shaping hair is proposed, comprising:

a first jaw and a second jaw arranged opposite one another and hinged together, a first treatment surface being supported by the first jaw and a second treatment surface being supported by the second jaw, the first and second treatment surfaces being configured to grip at least one lock of hair,

a liquid reservoir,

said first and/or second jaw additionally comprising:

a system for vaporizing the liquid to form steam, comprising at least one vaporization chamber which has an inner surface and is in communication via an injection tube with the liquid reservoir, said injection tube having a free end which forms a point for injecting the liquid into the vaporization chamber,

a system for dispensing the steam from the vaporization system, comprising at least one steam dispensing port directed toward the at least one lock of hair,

characterized in that the injection tube comprises an opening extending substantially along the length of the injection tube from the free end which forms the injection point, said opening being a shape that allows the liquid coming from the reservoir to run into the vaporization chamber in the event of accumulation and deposition of scale at the free end of the injection tube.

The hair-styling appliance proposed according to this second embodiment may comprise the following characteristics, taken alone or in combination:

the opening comprises at least one slit extending in an axial direction substantially parallel to the injection tube, preferably at least two slits extending on both sides of the injection tube, the at least two slits forming a plane extending preferentially parallel to the inner surface of the vaporization chamber; the opening is a cut-out over a half-section of the injection tube, extending in an axial direction substantially parallel to the injection tube, the injection tube is preferably arranged in the vaporization chamber in such a way that the cut-out is on the opposite side of the inner surface of the vaporization chamber; the injection tube is beveled at the free end forming the injection point; a ratio of a height of the vaporization chamber to an inner diameter of the injection tube is between 0.55 and 0.75; a hydrophilic layer extends over the inner surface of the vaporization chamber; the hydrophilic layer extends over the entire inner surface of the vaporization chamber; the hydrophilic layer comprises a woven material, preferentially glass fabric; a portion of the hydrophilic layer is arranged such that it runs partially into the free end of the injection tube; the vaporization chamber comprises a hydrophobic layer arranged below the injection tube at least at the injection point; the hydrophobic layer comprises polytetrafluoroethylene (PTFE); the hydrophobic layer is solely positioned below the injection point and over a surface comprised between 10 mm² and 2,000 mm², preferably comprised between 100 mm² and 1,000 mm², and more preferably comprised between 500 mm² and 600 mm², for example 552 mm²; the hydrophobic layer is an element mounted in the vaporization chamber, preferably in the form of a plate, and held in place by an immobilization device comprising an element for centering said mounted element relative to the injection point; the vaporization system also comprises a secondary vaporization chamber communicating fluid to the vaporization chamber and comprising a plurality of baffles; the steam dispensing system comprises a dispensing chamber in which the at least one steam dispensing port is arranged, said dispensing chamber receiving steam from the vaporization chamber. The dispensing chamber is preferably arranged laterally to the vaporization and secondary vaporization chambers. the vaporization system comprises a heating means located at least partially underneath the vaporization chamber and comprising a so-called positive temperature coefficient (PTC) electrical resistor or a ceramic; the first and the second treatment surfaces are substantially matching and flat or curved or corrugated.

DESCRIPTION OF THE FIGURES

Other characteristics, purposes and advantages of the invention will emerge from reading the detailed description below, and with reference to the appended drawings provided as non-limiting examples and in which:

FIG. 1 illustrates an overall view of a hair-styling appliance as described in this invention.

FIG. 2 shows a perspective view of a vaporization system according to one embodiment of this invention.

FIG. 3 shows a top view of the vaporization system according to the embodiment in FIG. 2.

FIG. 4A is a cross-section view of the vaporization system shown in FIG. 3 along axis A-A, according to a first embodiment of the vaporization chamber.

FIG. 4B is a cross-section view of the vaporization system shown in FIG. 3 along axis B-B, according to the embodiment of the vaporization chamber in FIG. 4A.

FIG. 5 is a cross-section view of the vaporization system shown in FIG. 3 along axis A-A, according to a second embodiment of the vaporization chamber.

FIG. 6A is a cross-section view of the vaporization system according to the embodiment in FIG. 5, at a first time.

FIG. 6B is a cross-section view of the vaporization system according to the embodiment in FIG. 5, at a second time subsequent to the first time illustrated in FIG. 6A.

FIG. 7 is a cross-section view of the vaporization system shown in FIG. 3 along axis A-A, according to a fourth embodiment of the vaporization chamber.

FIG. 8A is a cross-section view of the vaporization system according to the embodiment in FIG. 7, at a first time.

FIG. 8B is a cross-section view of the vaporization system according to the embodiment in FIG. 7, at a second time subsequent to the first time illustrated in FIG. 8A.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates an exploded perspective view of a steam hair-styling appliance for shaping hair. As explained above, the steam hair-styling appliance 1 generally comprises a first jaw 2 and a second jaw 3 arranged opposite each other and hinged together by means of a hinge-type joint 20. The maximum opening angle α (not shown) between the first and the second jaw is comprised between 5° and 60°, preferentially comprised between 10° and 20°, and more preferentially approximately equal to 15°.

A first treatment surface is supported by the first jaw 2 and a second treatment surface 4 is supported by the second jaw 3, the first and the second surfaces being designed to grip a lock of hair.

The first treatment surface and the second treatment surface 4 are generally matching surfaces. They may have different shapes, depending on the desired use of the hair-styling appliance 1, and are preferably interchangeable. Typically, the treatment surfaces are flat for use of the hair-styling appliance 1 as a straightener, or curved (not illustrated) for a use as a curler or wavy (not illustrated) for a use as a crimper. For example, EP0619087 describes a curling appliance. The treatment surfaces can also be uneven, i.e., comprise a plurality of protrusions such as teeth or pins (not illustrated).

The steam hair-styling appliance also comprises a liquid reservoir, typically a water reservoir (not shown in FIG. 1), or a reservoir containing a hair care agent, which can be embedded in one of the jaws, or alternatively arranged at a distance from the appliance in a so-called remote base, as proposed in document EP3025610.

As illustrated in FIGS. 2 and 3, the liquid reservoir communicates fluid via an injection tube 74 to a system for vaporizing 7 the liquid. The liquid reservoir is advantageously comprised in the jaw comprising the system for vaporizing 7 the liquid.

The vaporization system 7 comprises at least one vaporization chamber 71, referred to as the first vaporization chamber or main vaporization chamber, which occupies a first single volume, i.e., a volume defined without interruptions or without obstacles or barriers. The single volume can be substantially parallelepipedal and have, for example, a rectangular, square or trapezoidal cross section. This makes it possible to provide a good compromise between the compactness and the effectiveness of the vaporization system. The surface of the lower wall of the vaporization chamber 71, i.e., the wall forming the bottom of the vaporization chamber 71, is called the inner surface of the vaporization chamber 71. Thus, the fluid will be deposited by the injection tube 74 primarily on this inner surface in order to be turned into steam.

A so-called free end of the injection tube 74 forms a point of injection into the main vaporization chamber 71. The injection tube 74 preferably projects into the vaporization chamber 71, and the liquid contained in the reservoir can be injected into the main vaporization chamber 71 at this injection point. The injection tube 74 is therefore separate from the vaporization chamber 71, i.e., it is not the same part. The liquid contained in the reservoir is typically water or a hair care product.

The hair-styling appliance also comprises a steam dispensing system 7′, which is in communication with the vaporization system 7 and comprises one or multiple ports 75 for dispensing steam to a lock of hair.

The steam dispensing system 7′ can comprise, for example, a dispensing chamber 76 that receives steam from the vaporization chamber 71, and in which the at least one steam dispensing port 75 is arranged. The dispensing chamber 76 can extend laterally to the vaporization system 7, preferentially substantially along the entire length of the vaporization system 7. This enables a compromise between the compactness and the effectiveness of the vaporization 7 and dispensing 7′ systems.

The vaporization chamber 71 is preferably a compartment which is heated by a heating means 8, for example a heating means 8 positioned in contact with the vaporization chamber 71 such that the liquid injected into the vaporization chamber 71 can be vaporized separately from the heating of other components of the hair-styling appliance 1.

The heating means 8 can be positioned, for example, under the vaporization system 7, as can be ascertained from the exploded view in FIG. 1.

The heating means 8 can be arranged against the largest outer surface of the vaporization system 7, preferentially placed opposite the dispensing ports 75, and can extend so as to press at least partially against the lateral surfaces of the vaporization system 7.

Vaporization generally takes place in the vaporization system 7 and in the steam dispensing system 7′.

The vaporization system 7 preferably has a maximum outer volume of 110×35×12.5 mm, and has an inner volume that is sufficient for storing the scale contained in at least 35 liters of hard water with a hardness of 28° f. For example, the heating means 8 is designed to vaporize water in a sequence of 10 seconds followed by 10 seconds of rest, with a flow rate of ca. 1 g/min±0.5 g/min.

The vaporization system 7 can be composed of a metal, of an alloy, or of any heat-conducting material. The vaporization system 7 is typically made of aluminum and can be produced by casting or extrusion.

The vaporization system 7 can comprise multiple parts, in particular at least a cover. According to the exploded view in FIG. 1, the vaporization system 7 comprises a first part which comprises the vaporization chamber 71 and which presses against the heating means 8, on which is placed a second part, in this case a cover, comprising openings connected to the steam dispensing ports 75. The various parts are preferably sealed, for example by a silicone gasket.

In order to guarantee permanent contact and optimum operation, a leaf spring advantageously enables the vaporization system 7 to press the heating means 8.

The heating means 8 can typically be a so-called positive temperature coefficient (PTC) electrical resistor or a ceramic, but more generally any system which allows the vaporization chamber 71 to be heated in a manner consistent with the intended purpose.

Alternatively, the heating means 8 can comprise two heating elements arranged laterally against each side of the vaporization system 7. One of the two heating elements is advantageously pressed between an outer lateral surface of the vaporization chamber 71 and an outer surface of the steam dispensing system 7′ in order to heat the vaporization system 7 and the dispensing system 7′ simultaneously in a smaller space.

The heating means 8 can be controlled by a thermistor, for example a negative temperature coefficient (NTC) thermistor, which functions as a temperature sensor and is preferentially arranged above the injection point. The thermistor can make the hair-styling appliance 1 safer by blocking the liquid injection under certain conditions, for example according to the temperature of the heating means 8. Typically, a lower temperature limit is approximately 95° C. and an upper temperature limit is approximately 130° C., or within a reduced temperature range, a lower temperature limit is 105° C. and an upper temperature limit is 120° C., or even 110° C.

The injection tube 74 is advantageously arranged substantially in the center of the vaporization chamber 71. The end of the injection tube 74 which forms the injection point is arranged substantially in the first quarter of the length of the vaporization chamber 71. In order to improve the vaporization of the injected liquid, the injection point should in fact be placed in an area of the vaporization chamber 71 in which a maximum temperature occurs and at a distance from the inner walls of the vaporization chamber. The injection point should also be at a distance from the steam dispensing means 7′ in order to minimize the risk of ejecting hot water that has not had time to vaporize.

Preferably, the injection tube 74 has an outer wall that is at least 1 mm from the inner wall of the vaporization chamber 71, and the vaporization chamber has a height greater than 8 mm, in order to minimize scale deposition at the free end of the injection tube 74 and thus premature clogging.

The injection tube 74 can be composed of a material comprising or coated with a material to which scale does not adhere well in order to minimize scale deposition. Typically, the chosen material can be polytetrafluoroethylene (PTFE, also known under the registered brand name Teflon®), which has the advantage of having excellent anti-adhesive properties and of being highly resistant to heat. Preferably, at least one inner wall of the injection tube 74 is coated with PTFE such that the injection tube 74 can withstand high temperatures, in particular greater than 300° C., and has an inner wall with a very low friction coefficient, which minimizes the deposition of scale on the inner wall of the injection tube 74.

The injection tube 74 preferably has a large inner cross section in order to prevent premature clogging of the free end of the injection tube 74, for example. The diameter of the inner cross section can typically be greater than 3 mm, and preferably greater than 4 mm. In order to minimize the heat transfer from the walls of the vaporization chamber 71 to the liquid, the wall of the injection tube 74 can advantageously have a thickness of greater than 1 mm. A PPS (polyphenylene sulfide) bushing with an inner cross section of 6 mm and an outer cross section of 7 mm can be added to the injection tube 74 in order to minimize the heat transfer to the inner wall of the injection tube 74.

A ratio of the height of the vaporization chamber 71 to the diameter of the inner cross section of the injection tube 74 is preferably comprised between 0.55 and 0.75; typically, the ratio is approximately 0.6 for a height of 4.9 mm and an inner diameter of 3 mm. In fact, these dimensions have been optimized in order to guarantee the best possible resistance to scaling while still accommodating the dimensions of the various components.

The portion forming the free end of the injection tube 74 can advantageously have a specific shape that allows any accumulation of scale to be concentrated in a specific area while maintaining an area in which the liquid will be able to continue to run into the vaporization chamber 71 without being obstructed by the scale accumulation.

For example, the injection tube 74 is beveled at the free end forming the injection point as illustrated in FIG. 4A.

As an alternative or in addition, the injection tube 74 can comprise an opening extending substantially along the length of the injection tube from the free end forming the injection point. The opening has a shape which allows the liquid from the reservoir to flow into the vaporization chamber 71, even in the event of accumulation and deposition of scale at the free end of the injection tube 74.

In an exemplary embodiment, the opening of the injection tube 74 is a cut-out over a half-section of the injection tube 74, which extends in an axial direction substantially parallel to the injection tube 74. In the exemplary embodiment illustrated in FIGS. 2 to 5, the injection tube 74 is arranged in the vaporization chamber 71 in such a way that the cut-out is on the opposite side of the wall which forms the bottom of the vaporization chamber 71. In an exemplary embodiment in which the vaporization chamber 71 is closed by a plate forming a cover, this typically means that the cut-out of the tube 74 is thus oriented toward the plate which forms the cover.

In an exemplary embodiment illustrated in FIG. 7, the opening of the injection tube 74 comprises at least one slit extending in an axial direction substantially parallel to the injection tube 74. The opening can preferably comprise two slits extending on both sides of the injection tube 74.

According to a preferred, but not compulsory, exemplary embodiment, the inner surface of the vaporization chamber 71 is covered, at least partially, by a hydrophobic layer 9 positioned below the injection point. The hydrophobic layer 9 allows the vaporization to be shifted further into the vaporization chamber 71 rather than to take place under the injection point so that scale deposits do not build up below the injection point. The hydrophobic layer 9 is in fact characterized by a high surface tension.

The hydrophobic layer 9 advantageously comprises polytetrafluoroethylene (PTFE). PTFE is in fact a material that can withstand high temperatures (in particular greater than 300° C.) and has a very low friction coefficient, which minimizes scale deposition at the injection point since water cannot remain there.

According to an exemplary embodiment, the hydrophobic layer 9 is positioned solely below the injection point. This means that only a surface below the injection point is covered by the hydrophobic layer 9, which therefore does not cover the entire inner surface of the vaporization chamber 71. In particular, the hydrophobic layer 9 can cover a surface comprised between 10 mm² and 2,000 mm², preferably comprised between 100 mm² and 1,000 mm², and more preferably comprised between 500 mm² and 600 mm². The hydrophobic layer 9 can typically cover the inner surface which forms a bottom of the vaporization chamber 71, over a surface of approximately 552 mm².

The hydrophobic layer 9 can have a flat, preferably substantially rectangular or triangular, shape. It can also assume a three-dimensional shape defined by, for example, inclined planes, making it possible to improve the glide of the liquid in order to move the vaporization point away from the free end of the injection tube 74. Such a three-dimensional shape can also help spread the liquid more effectively when it arrives in the vaporization chamber by breaking up the large droplets and by spreading them as smaller droplets over the entire inner surface of the vaporization chamber 71. The effectiveness of the vaporization is thus improved, and the risk of scaling (and of clogging) of the appliance is simultaneously reduced. In the embodiment in which the hydrophobic layer 9 has a three-dimensional shape, the shape of the hydrophobic layer 9 can also be created during the production of the vaporization chamber 71, typically by incorporating the shape into the mold.

In an exemplary embodiment illustrated in FIGS. 4A and 4B, the hydrophobic layer 9 has, for example, a pyramid shape. Alternatively, the hydrophobic layer 9 can have a truncated pyramid shape.

In an exemplary embodiment, the proposed hydrophobic layer 9 is formed by applying a hydrophobic material to an inner surface of the vaporization chamber 71. The hydrophobic material can typically be applied like a paint or coating, or sprayed on the inner surface of the vaporization chamber 71.

The hydrophobic layer 9 is advantageously an element mounted in the vaporization chamber 71. The mounted element is held in position in the vaporization chamber 71 by an immobilization device comprising an element for centering 710 the mounted element relative to the injection point.

In the example of the vaporization chamber 71 illustrated in FIGS. 2 and 3, the centering element 710 comprises a centering half-pin 710 a, which is formed in the vaporization chamber 71 and designed to cooperate with a matching notch 9 a formed in the mounted element 9.

As an alternative or in addition, the inner surface of the vaporization chamber 71 comprises a hydrophilic layer 10, i.e., a layer characterized by a low surface tension. The hydrophilic layer 10 extends over all or part of the inner surface of the vaporization chamber 71.

The hydrophilic layer 10 can be positioned solely below the injection point, meaning that only a surface below the injection point is covered by the hydrophilic layer 10. The hydrophilic layer 10 preferably extends over the entire inner surface of the vaporization chamber 71 so as to maximize the diffusion of the liquid.

The hydrophilic layer 10 preferentially comprises a woven material, for example a glass fabric, which allows the heating phenomenon to be minimized significantly.

According to a specific exemplary embodiment, which is illustrated specifically in FIGS. 4A and 4B, the vaporization chamber 71 comprises a hydrophilic layer 10 which is covered, at least partially, by a hydrophobic layer 9. In this embodiment, the liquid injected at the injection point falls as a droplet onto the hydrophobic layer 9, and stays in the shape of a sphere due to the high surface tension of the hydrophobic material constituting the hydrophobic layer 9, this sphere then sliding toward the hydrophilic layer 10, away from the injection point. Since the hydrophilic layer 10 has a low surface tension, the water droplet is able to vaporize instantaneously. This reduces the formation of scale, which will be deposited in any event away from the injection point, if at all.

Advantageously but not compulsorily, and as shown specifically in FIGS. 2 and 3, the liquid vaporization system 7 can also comprise a second vaporization chamber or secondary vaporization chamber 72, which communicates fluid to the first vaporization chamber 71 and which occupies a separate, second volume. The first vaporization chamber 71 is thus arranged upstream of the second vaporization chamber 72, in the direction of the steam flow.

In this embodiment, the liquid injected into the vaporization chamber 71 is turned into steam in at least two separate vaporization chambers (71, 72). This allows undesired scale to be effectively retained and the resistance of the hair-styling appliance 1 to limescale to be improved, consequently prolonging its useful life.

The second vaporization chamber or secondary vaporization chamber 72 preferably comprises interruptions or obstacles in the form of baffles 73 for creating a labyrinthine path for the steam.

A baffle 73 means any obstacle or barrier placed in the chamber that creates irregular flows of steam, as zigzags for example, thus reducing the flow velocity in the secondary vaporization chamber 72 and increasing the contact with the surfaces of the various walls of the chamber 72. This allows any droplets of liquid to be vaporized, thereby assuring complete vaporization of the liquid, the heat exchange surface being increased by the presence of the baffles 73. The baffles 73 can be distributed parallel to one another, for example. This allows the steam to flow in a regular configuration, thus trapping scale effectively in the second vaporization chamber 72.

The first volume occupied by the first vaporization chamber 71 is preferably greater than the second volume occupied by the second vaporization chamber 72, even at least two times greater, so as to enable rapid vaporization in the first volume while retaining the compactness of the vaporization system 7.

In this embodiment, the proposed dispensing chamber 76 can be arranged laterally to the vaporization chamber 71 and to the second vaporization chamber 72, preferentially along substantially the entire length of the vaporization system 7.

EP2591698 describes such an arrangement and the corresponding operation in detail.

Specific exemplary embodiments schematically depicting the vaporization system 7 while in operation are provided in FIGS. 6A, 6B and 8A, 8B in order to illustrate the advantages procured by the characteristics described above.

In a first exemplary embodiment illustrated in FIGS. 6A and 6B, the injection tube 74 comprises an opening with a cut-out over a half-section, and the inner surface of the vaporization chamber 71 is covered by a hydrophobic layer 9, which covers all or part of the inner surface of the vaporization chamber 71. In operation, according to FIG. 6A, at a first time T1, typically during a first use of the hair-styling appliance 1, the liquid from the reservoir is injected into the vaporization chamber 71 by the injection tube 74, at the free end forming an initial injection point 11.

A rapid rise in temperature causes the injected water to vaporize upon contacting the hydrophobic layer 9, at a vaporization point away from the initial injection point 11. Because the injected liquid water may contain minerals, limescale or scale gradually accumulates at the end forming the initial injection point 11. Scale may gradually be deposited inside the injection tube 74 until the end is clogged.

According to FIG. 6B, a scale plug 12 obstructs the end of the injection tube 74 at a time T2 subsequent to T1, for example after more than 10 liters of hard water, typically with a hardness of 28° f, has been injected into the vaporization chamber 71. The water then flows into the vaporization chamber 71 at another injection point 11′ positioned upstream of the injection tube 74 relative to the initial injection point 11. The water can potentially flow on both sides of the injection tube 74, or over the scale plug 12.

In this exemplary embodiment, the injection point 11′ gradually shifts along the length of the cut-out of the injection tube 74 throughout the use of the hair-styling appliance 1 as the scale accumulates. In other words, the moment when the injection point is obstructed by scale is significantly postponed over time because only when the entire length of the cut-out of the injection tube 74 becomes obstructed by scale will water injection no longer be possible. The resistance of the appliance to scaling is thus considerably improved.

In a second exemplary embodiment illustrated in FIGS. 8A and 8B, the injection tube 74 comprises an opening with a slit at the free end, and the inner surface of the vaporization chamber 71 is covered with a hydrophobic layer 9 covering all or part of the inner surface of the vaporization chamber 71. In operation according to FIG. 8A, at a first time T1′, typically during a first use of the hair-styling appliance 1, the liquid from the reservoir is injected into the vaporization chamber 71 by the injection tube 74 at the free end forming an initial injection point 11.

As in the previous example, a rapid rise in temperature causes the injected water to vaporize on contact with the hydrophobic layer 9 at a vaporization point at a distance from the initial injection point 11. As the injected liquid water may contain minerals, scale gradually accumulates at the end forming the initial injection point 10 [sic]. Scale may gradually accumulate inside the injection tube 74 until the end is clogged.

According to FIG. 8B, a scale plug 12 obstructs the end of the injection tube 74 at a time T2′ subsequent to T1′, for example after more than 10 liters of hard water, typically with a hardness of 28° f, has been injected into the vaporization chamber 71. The water then flows into the vaporization chamber 71 at another injection point 11′ positioned upstream of the injection tube in relation to the initial injection point 11. In the particular case in which the opening comprises two slits on both sides of the injection tube 74, the water will be able to flow at two injection points on both sides of the injection tube 74.

As in the previous example, the injection point 11′ gradually shifts along the length of the slit throughout the use of the hair-styling appliance 1 as the scale accumulates. In other words, the moment when the injection point is obstructed by scale is significantly postponed over time because only when the entire length of the cut-out of the injection tube 74 becomes obstructed by scale will water injection no longer be possible. The resistance of the appliance to scaling is thus considerably improved.

The addition of an opening on the injection tube 74 and/or the presence of a hydrophobic layer 9 at the injection point thus enable(s) an increase of the useful life of the appliance 1 due to better resistance to scaling.

The reader will have understood that numerous modifications can be made without actually exceeding the new teachings and advantages described here. Consequently, all modifications of this type are intended to be incorporated within the scope of the hair-styling appliance presented herein.

BIBLIOGRAPHICAL REFERENCES WO2014064660, FR2987242, EP0619087, EP3025610, EP2591698 

1. A steam hair-styling appliance for shaping hair, comprising: a first jaw and a second jaw arranged opposite one another and hinged together, a first treatment surface being supported by the first jaw and a second treatment surface being supported by the second jaw, the first and second treatment surfaces configured to grip at least one lock of hair, a liquid reservoir, said first and/or second jaw additionally comprising: a system for vaporizing a liquid to form steam, comprising at least one vaporization chamber having an inner surface and in communication via an injection tube with the liquid reservoir, said injection tube having a free end which forms a point for injecting the liquid into the at least one vaporization chamber, a system for dispensing the steam from the system for vaporizing, comprising at least one steam dispensing port directed toward the at least one lock of hair, wherein the injection tube comprises an opening extending substantially along a length of the injection tube from the free end which forms the point, said opening being a shape configured to allow the liquid coming from the liquid reservoir to run into the at least one vaporization chamber in the event of accumulation and deposition of scale at the free end of the injection tube.
 2. The steam hair-styling appliance according to claim 1, wherein the opening comprises at least one slit extending in an axial direction substantially parallel to the injection tube.
 3. The steam hair-styling appliance according to claim 2, wherein the at least one slit comprises at least two slits extending on sides of the injection tube, the at least two slits defining a plane extending substantially parallel to the inner surface of the at least one vaporization chamber.
 4. The steam hair-styling appliance according to claim 1, wherein the opening is a cut-out over a half-section of the injection tube, extending in an axial direction substantially parallel to the injection tube.
 5. The steam hair-styling appliance according to claim 4, wherein the injection tube is arranged in the at least one vaporization chamber such that the cut-out is on an opposite side of the inner surface of the at least one vaporization chamber.
 6. The steam hair-styling appliance according to claim 1, wherein the injection tube is beveled at the free end forming the point.
 7. The steam hair-styling appliance according to claim 1, wherein a ratio of a height of the at least one vaporization chamber to an inner diameter of the injection tube is between 0.55 and 0.75.
 8. The steam hair-styling appliance according to claim 1, wherein a hydrophilic layer extends over the inner surface of the at least one vaporization chamber.
 9. The steam hair-styling appliance according to claim 8, wherein the hydrophilic layer extends over the entire inner surface of the at least one vaporization chamber.
 10. The steam hair-styling appliance according to claim 8, wherein the hydrophilic layer comprises a woven material.
 11. The steam hair-styling appliance according to claim 8, wherein a portion of the hydrophilic layer runs partially into the free end of the injection tube.
 12. The steam hair-styling appliance according to claim 1, wherein the at least one vaporization chamber comprises a hydrophobic layer arranged below the injection tube, at least at the point.
 13. The steam hair-styling appliance according to claim 12, wherein the hydrophobic layer comprises polytetrafluoroethylene
 14. The steam hair-styling appliance according to claim 12, wherein the hydrophobic layer is positioned below the point and on a surface measuring between 10 mm² and 2,000 mm²
 15. The steam hair-styling appliance according to claim 12, wherein the hydrophobic layer is mounted in the at least one vaporization chamber and held in position by an immobilization device comprising an element for centering the hydrophobic layer relative to the point.
 16. The steam hair-styling appliance according to claim 1, wherein the at least one vaporization chamber includes first and second vaporization chambers, wherein the second vaporization chamber communicates fluid to the first vaporization chamber and comprises a plurality of baffles.
 17. The steam hair-styling appliance according to claim 1, wherein the system for dispensing further comprises a dispensing chamber in which the at least one steam dispensing port is arranged, said dispensing chamber receiving steam from the at least one vaporization chamber.
 18. The steam hair-styling appliance according to claim 16, wherein the system for dispensing further comprises a dispensing chamber in which the at least one steam dispensing port is arranged, said dispensing chamber receiving steam from the at least one vaporization chamber, and wherein the dispensing chamber is arranged laterally to the first vaporization chamber and to the second vaporization chamber.
 19. The steam hair-styling appliance according to claim 10, wherein the woven material is glass fabric. 